Incline bench vs flat

I've heard a lot of the virtues of incline bench being better for isolating chest where flat incorporates front delts a lot. And I think best advice is to do them both. But I have a question on something that doesn't seem intuitive.

Taking the bench from flat to straight up, you go from flat bench to seated shoulder press. I would think the more you incline from flat, the more you incorporate your delts until finally you get to seated shoulder press which is nearly all delts and little chest.

Why would incline bench incorporate chest more than flat bench or do I have the wrong impression why incline bench is so often recommended for chest?

I've heard a lot of the virtues of incline bench being better for isolating chest where flat incorporates front delts a lot. And I think best advice is to do them both. But I have a question on something that doesn't seem intuitive.

Taking the bench from flat to straight up, you go from flat bench to seated shoulder press. I would think the more you incline from flat, the more you incorporate your delts until finally you get to seated shoulder press which is nearly all delts and little chest.

Why would incline bench incorporate chest more than flat bench or do I have the wrong impression why incline bench is so often recommended for chest?

Actually decline presses are better at isolating the chest and minimizing deltoid involvement.

The bench press may be the most popular and widely used exercise used for developing the chest (Thompson, 1994). But go into any gym today and you will see quite a few different variations being done. There’s the decline, the incline, the flat bench and to make things even more complicated, all of these can be done with dumbbells. Is one better than the others? Which one should you use and what does each develop?

Well, this is where we must begin to separate popular ‘gym myths’ from reality. First let’s look at the claims of many bodybuilders. Most believe the angle of the bench has lots to do with what part of the chest you will use. So it is a pretty common belief among weightlifters that the decline bench targets the sternocostal head of the pectoralis major (the lower pecs) and the incline bench hits the clavicular head of the pectoralis major (the upper pecs). So obviously the flat bench must hit a little of both. What about the grip position? Should we use a wide grip or is a narrow grip? I’m sure most of us have heard that a wide grip uses more chest and shoulders and a narrow grip uses more triceps.

Is this common advice just another fine example of the ‘gym myth’ or is there actually some science to back these anecdotal claims? Before we attempt to answer this burning question let’s first take a look at what really happens when the bench press is performed. As most of us are aware the major muscle used in the movement of the bench press is the pectoralis major. While the pectoralis major is actually one muscle, it has two heads -- the clavicular head and the sternocostal head. The clavicular head or the upper pecs originate at the middle part of the clavicle. The sternocostal head or lower pecs originate at the costal cartlidges of the first six ribs and the adjoining portion of the sternum. Both heads span the chest and eventually join and insert on the humerus or the bone of the upper arm. It is pretty much accepted by sport scientists that the upper pecs are responsible for shoulder flexion or moving the arm upward and the lower pecs are responsible for shoulder extension or moving the arm downward (Lockhart 1974). So at this point it still seems logical to believe that the decline position may actually hit the lower pecs and the incline will hit the upper pecs.

But wait...before we draw any conclusions, let’s take a quick look at some of the other muscles involved in moving the bench press. First we have the triceps brachii. The major function of the triceps is to extend the elbow and shoulder joints. The triceps brachii actually consist of three heads (long, lateral, and medial). The medial and lateral heads attach to the upper arm and elbow performing extension of the elbow joint while the long head attaches to the scapula to extend the shoulder.

Next we have the deltoids. While the deltoid is only one muscle it actually attaches in three places giving it three distinct heads (anterior, lateral, and posterior). While the posterior and lateral heads are used as stabilizers in the bench press we are only going to be concerned with the anterior or front deltoids (McCaw, 1994). The front deltoids are responsible for flexion, by moving the arm upward and horizontal adduction, which is moving the arm toward the chest.

The last muscle we will take a look at is the latissimus dorsi or the lats. The lats in this case, act as an adductor by pushing the arm toward the midline of the body. The lats however, are thought to play only a very minor part in the actual moving of the bench press. They have been shown to be effective just prior to the bottom phase of the lift (Barnett, 1995).

Now what does science have to say about the effectiveness of all of these variations in the bench press? As many of us are aware, when a muscle contracts it produces electrical energy. The higher the electrical energy the more work the actual muscle is producing. By attaching electrodes to the skin over the bellies of each of these muscles this electrical energy can be measured and read using an electromyograph (EMG). EMG studies can be then be performed on subjects to determine which muscles each of these variations in the bench press may effect. In a recent study Barnett et al (1995) examined the EMG activity of the upper pecs, the lower pecs, the triceps, the front deltoids and the lats using the decline, flat and incline bench press. This study will be quite useful in shedding some light on this confusing subject of pectoral development. So let’s get started!

The Sternocostal Head

One of the most common assumptions in the world of iron is that the decline bench is the best for developing the lower pecs. However, this familiar premise may be nothing more than another unfounded gym myth. According to the Barnett EMG study, the flat bench produced much more electrical energy in the lower pecs than did either the decline or incline positions. "I agree with this research" says NPC National Champion and pro bodybuilder Jay Cutler, "The flat bench is much better for lower pec development than the decline."

But what is the best grip to use? EMG studies have also shown that when doing the flat bench, the muscle fibers of the lower pecs are activated the most when using a wide grip. "This is very much true," adds Fred "Dr. Squat" Hatfield, Ph.D. "A wide grip with the elbows out will cause much more lower pec activation." However, whether you choose to use a wide or narrow grip, we can assume that using the decline position to target the lower pecs is just not justified. Eddie Robinson, IFBB pro bodybuilder states, "I feel the flat bench press, with a wide grip is best for over all pec development, but you do not want to go so wide with the grip that you over stress the shoulders."

The Clavicular Head

Now we all know that the incline bench hits the upper pecs. Right? Since the upper pecs seem to help to raise the arm, this would make sense. The incline position would put the arm in more of a flexed position than either the flat or decline positions. According to EMG studies this advice seems to be pretty much true. The Barnett study tells us that the incline position produces just slightly more electrical energy in the upper pecs that either the flat or decline positions. However, the flat bench was found to be very close. While the difference between the two was considered insignificant, the slight advantage of the incline over the flat bench in upper pec activation may be just what some of us need to further develop the upper pecs. "This is all very true," says Robinson. "There is no doubt the incline bench hits the pecs more than the flat bench."

Cutler agrees and says, "I personally feel upper pec development is very important for a bodybuilder. So I concentrate more on the incline bench that I do the flat bench." While the incline position may provide slightly greater upper pec stimulation Hatfield contends, "The same thing can be accomplished by using the flat bench. I would suggest lowering the bar to the upper pecs instead of the lower pecs (as normal), using a wide grip with the elbows out."

Nevertheless, if you are going to use the incline position to target the upper pecs, a narrower grip has been shown to best activate them. Professional bodybuilder Mike Francois agrees and says "A grip that is just a little bit wider than shoulder’s width really hits my upper pecs best." But Sal Arria, D.C., founder of the International Sport Science Association and former powerlifting champion warns: "Using a wide grip can involve too much front deltoid and can cause the deltoids to slam against the acronium process, causing trauma to the muscle."

The Triceps Brachii

I’m sure most of us have been told that a narrow grip hits more triceps than the wide grip. The close grip bench is widely used by powerlifters to develop strength in the triceps to accomplish those massive bench press attempts. According to the EMG study this is very true. The narrow grip when done in a flat position, produced more electrical energy than the incline or decline positions. It should be noted though, that the decline position was pretty close. Cutler explains, "While the decline may be close, I prefer to target the triceps using the flat bench with a narrow grip." Professional bodybuilder Mike Francois agrees, "The flat bench with a narrow grip is a great mass builder." "A narrow grip means your hands should be at your body’s width," Dr. Arria warns, "If you want to create a permanent wrist injury, go with a extremely narrow grip."

The Anterior Deltoid

Since the front deltoids are used for flexion of the arm, it makes since that the incline bench would activate the deltoids much more than the flat or decline positions. Once again our EMG study agrees. The incline bench press with a wide grip produced more electrical energy than the narrow grip. Francois remarks, "I agree! The greater the incline of the bench the more the front delts will be activated." Dr. Arria adds: "While the narrow grip is a stronger position, the wider grip produces more stress to the muscle."

The Latissimus Dorsi

Many of us were probably unaware that the lats were even involved in the bench press. However, EMG studies do show that the lats are activated for a short period of time just prior to the start of the bottom phase of the lift. Robinson states, "There is no doubt in my mind that the lats are used to help get the weight moving off the chest." However, while the lats are activated briefly in the pressing movement, it should be noted that this activity is considered to be very small when compared to that of the other muscles used in the bench press. In any case, the decline bench seemed to activate the lats much more that either the flat of incline positions. Also the wider the grip the greater the activation of the lats. "While the lats are not so much directly related to the push motion of the bench press, they are directly related to the stabilization of the torso," says Dr. Arria. "This is very important because greater trunk stabilization means that the dynamic load on the muscle is more specific."

While the lats appear to help get the bench moving off the chest and provide stabilization, no variation of the bench press should ever be considered to be a good exercise for developing the lats. But that in no way means that good lat development is not important for optimal chest development. Francois agrees and says, "The lats are definitely a factor in the movement and stabilization of the bench press, but there are certainly much better ways to develop good lats."

There are a lot of articles on decline not being worth your time, because it engages less chest and compensates with lats - which should be done on back day. While flat uses most chest, and incline still has most focus on chest shelf, but does compensate with shoulders the higher your incline gets.